Composition being capable of imparting conductivity and non-tackifying property, paint using the composition, and roller

ABSTRACT

A composition which is capable of imparting electrical conductivity and non-tackifying property, comprising (A) a carbon fluoride in which a ratio F/C of fluorine atom to carbon atom is more than 0.5 and less than 1.0 and (B) at least one selected from the group consisting of a thermoplastic resin, a thermosetting resin and a rubber, a paint composition containing the same, and a semi-electrically conductive roller for electrostatic copying machine having an electrically resistive layer formed from the composition.

TECHNICAL FIELD

The present invention relates to a composition containing a carbonfluoride and capable of imparting electric conductivity andnon-tackifying property, a paint composition using the above-mentionedcomposition, and a roller having an electrically resistive layer beingformed using the composition.

BACKGROUND ART

Fluorine-containing rubbers have excellent properties such as heatresistance, oil resistance, solvent resistance and chemical resistanceas compared with rubbers for general uses, and are widely used asindustrial materials in the field where these properties are required.

The fluorine-containing rubbers have been usually used by vulcanizingand molding a vulcanizable fluorine-containing rubber composition, whichis prepared by blending a vulcanizing agent, a vulcanizationaccelerator, an acid receiving agent, a vulcanizing auxiliary, aninorganic filler and the like.

As the above-mentioned mixing components, examples of the vulcanizingagent are a polyamine or its salt, an organic peroxide, a polyhydroxylcompound and the like. As the vulcanization accelerator, examples are anorganic tertiary or quaternary compound containing nitrogen orphosphorus and the like, and as the acid receiving agent, examples are abivalent metal oxide or a hydroxide and the like. As the vulcanizingauxiliary, examples can be mentioned a compound having a plurality ofvinyl groups or aryl groups. In addition thereto, there are admixedinorganic fillers, if necessary, such as carbon black, silica, clay,diatom earth, talc, calcium carbonate and the like for the purposes toimprove and enhance mechanical properties of mainly thefluorine-containing rubbers.

Further, in order to enhance abrasion resistance of the vulcanizedrubber, there are admixed, as a solid lubricant, molybdenum disulfideand graphite or a low molecular weight polytetrafluoroethylene and/or acarbon fluoride as disclosed in JP-B-40168/1981.

Also in order to obtain a high level chemical resistance and elusionresistance which are required in a semiconductor production process andthe like, there is a case where a carbon fluoride is admixed asdisclosed in JP-A-169845/1987.

These fluorine-containing rubbers are electrically insulative materialshaving a volume specific resistance exceeding 10¹² Ωcm. Therefore therewas a problem that the molded fluorine-containing rubbers are apt tocharge with static electricity thereon, and are susceptible tocontamination due to dusts. Thus for the use in the semiconductorproduction process, it was very difficult to handle those rubbersbecause of dust generation. Also in a pressure roller, paper feed rollerand the like, those rubbers cause troubles that a paper sticks to theroller due to static electricity and toner powders stick or scatter.Also in the use for fuel tubes of automobiles, a spark generated bystatic electricity becomes a cause for a fire and it is very dangerous.

Therefore it is attempted to admix an electrically conductive materialin a fluorine-containing rubber composition. As the electricallyconductive material, examples are a carbon material such as carbonblack, graphite powder or carbon fiber, and a metal powder.

However if the carbon black is admixed in an amount sufficient forobtaining electric conductivity, there occurs a problem that hardness ofthe rubber is increased because of a structure of carbon black. Themixing of powder such as graphite powder and carbon fiber havinganisotropic shape causes a problem that roughness of the rubber surfaceis increased, and the admixing of metal powder causes a problem that anexcellent chemical resistance inherent to the fluorine-containing rubberis impaired.

Also the desired electric conductivity varies depending on uses. In theabove-mentioned various uses, the lower the volume specific resistanceis, the more preferable if it is not more than 10⁸ Ωcm. The compositionis selected within such a range as not sacrificing other properties ofthe fluorine-containing rubber composition.

For example, in a fixing roller of an electrostatic copying machine, thelower the volume specific resistance is, the more preferable if it isnot more than 10⁸ Ωcm as mentioned above in order to preventelectostatic offset (a phenomenon wherein the roller is electricallycharged due to a friction to paper, and an un-fixed toner image issucked or repels due to this static electricity, thus disturbing thefixed image). At the same time, an excellent non-tackifying property isrequired to prevent hot offset (a phenomenon wherein the fixed image isdisturbed because the toner heated and molten by the roller sticks tothe roller).

For this purpose, attempts to add the carbon materials have beenhitherto made, but the addition of the carbon materials in an amountenabling sufficient conductivity to be obtained causes a problem thatnon-tackifying property lowers. Thus a composition satisfying bothelectric conductivity and non-tackifying property is desired.

However a specific range of electric conductivity is desired inso-called semi-electrically conductive rollers of the electrostaticcopying machine such as a charging roller, transferring roller anddeveloping roller. Concretely in the charging roller, the volumespecific resistance is required to be controlled to be in the range of10⁸ to 10¹² Ωcm. It is not allowed that even a part of the rollerdeviates from this range. That is to say, if it is not less than 10¹²Ωcm, a necessary electric charge is not given to a photosensitive drum,and if it is not more than 10⁸ Ωcm, the photosensitive drum and highvoltage power source are damaged by an over-current.

In order to use a fluorine-containing composition wherein usualelectrically conductive substances are mixed, for these applications,there is a problem that accurate control of the mixing amounts andsufficient kneading are required. This is because it is difficult tocontrol the volume specific resistance to be in a narrow range of 10⁸ to10¹² Ωcm since the resistance lowers sharply when the usual electricallyconductive substance added step by step exceeds a certain amount.Therefore there is desired the fluorine-containing composition havingelectric conductivity and non-tackifying property which enables changesin mechanical properties such as increase in hardness and a surfaceroughness and non-tackifying property to be minimum without impairinginherent excellent properties of the fluorine-containing rubbers such aschemical resistance.

On the contrary, fluorine-containing rubber paints are widely used asindustrial materials to be coated or impregnated on various substrates,for example, metals, plastics, rubbers, glasses, ceramics, fabrics,non-woven fabrics, fibers, porcelains and others because of excellentheat resistance, weatherability, oil resistance, solvent resistance andchemical resistance which fluorine-containing rubbers have.

Usual fluorine-containing rubber paints are those prepared by mixing anaminosilane compound as a coupling agent in an aqueous dispersion offluorine-containing rubber as mentioned in JP-B-53671/1983, and ifnecessary, various additives are added thereto.

For instance, in JP-B-35432/1987, it was found out that by mixing afluorine-containing resin, non-tackifying property and lubricity couldbe given to a surface of a coating without impairing adhesivity to asubstrate, and further in addition, the coating having an excellentcompression recovering property.

Also in JP-B-38393/1987, it was found out that electric conductivitycould be imparted on an obtained film without impairing any features offluorine-containing rubber paints by mixing an electrically conductivesubstance selected from the group consisting of a carbon black, agraphite, a metal and an antistatic agent.

However as mentioned hereinabove, it is required thatfluorine-containing rubber paints have a particular range of volumespecific resistance as the paints for the production ofsemi-electrically conductive rollers for electrostatic copying machine.Therefore when it is intended to control electric conductivity by mixingcarbon materials such as carbon black as the electrically conductivesubstance in the fluorine-containing rubber paints, there is a problemthat accurate control of the mixing amount and homogeneous dispersionare required. That is to say, this is because when usual electricallyconductive substances added step by step exceed a certain amount, theresistance changes sharply. Among various electrically conductivesubstances, the carbon black has a feature that the deterioration ofnon-tackifying property, chemical resistance and the like offluorine-containing rubbers can be minimized. However the carbon blackbeing excellent in electric conductivity has a progressed structure, andis in difficult to disperse fluorine-containing rubber paints and largerin increase in viscosity. Also there is a marked tendency that thefluorine-containing rubber becomes harder and the surface rougheness isincreased.

When the hardness increases, in order to obtain an effective contact tothe drum and paper, it is necessary to press by a strong force, and as aresult, there occurs disturbance of the drum and image. When the surfaceroughness is increased, there occurs irregular contact to the drum andpaper and disturbance of the image.

Therefore there is required fluorine-containing rubber paints havingelectric conductivity and non-tackifying property which can minimizechanges in the surface roughness, non-tackifying property and mechanicalproperty such as hardness without causing a sharp change in theresistance by a change in the mixing amount and impairing excellentproperties inherent to fluorine-containing rubber such as chemicalresistance.

As mentioned above, an electrically resistive layer having electricconductivity and non-tackifying property is strongly demanded forsemi-electrically conductive rollers for electrostatic copying machine.This matter is stated further concretely.

A corona discharge method and contact charge method have been adopted ina charging or transferring process of an electrostatic copying machine,laser printer and facsimile which utilize an electro-photographic methodas one of image forming methods. First, in the corona discharge method,a machine structure is simple, but there are disadvantages that there isa generation of ozone, which not only causes an adverse effect onenvironment but also shorten a life of an organic photoreceptor. On thecontrary, in the contact charge method, because there is no ozonegeneration and in addition, energy loss is small, a high pressure powersource can be small-sized. In addition, since power consumption isdecreased, this method is suitable for making a size of a whole machinesmaller. The contact charge method in the charging process is one forelectrically charging a surface of a photosensitive drum by bringing thesemi-electrically conductive roller into contact with a surface of aphotosensitive drum and rotating it. This method is proposed in, forinstance, JP-A-843/1975, JU-A-88645/1983, JP-A-194061/1983,JP-A-142569/1989 and JP-A-311972/1992.

An electrostatic copying machine using this contact charge method has astructure as stated, for instace, in JP-A-311972/1992. The structurethereof is, for example, one as shown in FIG. 1. A photosensitive drum 1usually comprises an organic photoreceptor, and there may be usedselenium, CdS, amorphous silicon and the like. A charging roller 2 isdisposed being brought into contact with the above-mentionedphotosensitive drum 1. A developing device 3, a transferring roller 5and a toner cleaner 7 are arranged in the clockwise direction, certeringaround the charging roller 2. Further a fixing roller 6 for fixing of atransferred paper 4 fed out from the transferring roller 5 is disposedin the vicinity of the photosensitive drum 1 between the transferringroller 5 and the toner cleaner 7.

The image forming process of the electrostatic method using thesemi-electrically conductive roller is briefly explained hereinbelow.

The charging roller 2 the comprising the semi-electrically conductiveroller having an elasticity is rotated on the outer circumferentialsurface of the photoconductive drum 1 (for instance, linear speed 60mm/sec) rotating in the direction of an arrow, by the photosensitivedrum 1, being partly elastically deformed. The outer surface of thephotosensitive drum 1 is electrically charged by bringing it intocontact with this charging roller 2. On the surface of the thus chargedphotosensitive drum 1 is formed an electrostatic latent imagecorresponding to an original image by means of an exposing mechanismportion 8, and the latent image is made into a visible image by adeveloping device 3. Then an electric charge reverse to the visibleimage of toner particles which is formed on the photosensitive drum 1 isapplied to a transfer paper through the transferring roller 5 totransfer the visible image of the toner particles onto the transferpaper 4. The visible image of the toner particles electrostaticallysticking to the transfer paper 4 is fused and deposited on the transferpaper 4 by the heated fixing roller 6 to give a fixed image.

In this case, 85 to 95% of the toner sticking onto the surface of theabove-mentioned photosensitive drum 1 by means of the transferringroller 5 is transferred on the drum but the remaining toner after thistransfer is nearly completely removed by means of a toner cleaner 7,then is wholly subjected to an emission of light by an eraser 9, andinitiated to make preparation for the subsequent charging.

As mentioned above, for the electrostatic copying machine and the like,there are used many semi-electrically conductive rollers such as thecharging roller, developing roller, transferring roller and fixingroller. As shown in FIG. 2, such a semi-electrically conductive rollerto be used is such that a metallic core roll and an electricallyconductive elastic layer 11 on the outer circumference thereof areformed and an electrically resistive layer 12 is formed over thiselectrically conductive elastic layer 11.

As the materials for the electrically conductive elastic layer, thereare used ones having a volume specific resistance of not more than 10⁵Ωcm, preferably not more than 10³ Ωcm and a rubber hardness (JIS A) of20 to 50 degrees, preferably 25 to 40 degrees. This layer comprisesgenerally a composition prepared by mixing an electrically conductivepowder (carbon black, metal powder and the like) into a synthetic rubbersuch as a silicone rubber, ethylene propylene rubber, nitrile rubber andurethane rubber.

Also as the materials for the electrically resistive layer, those havinga volume specific resistance of 10⁶ to 10¹² Ωcm, preferably 10⁸ to 10¹²Ωcm are used. This resistive layer generally comprises a polar rubbersuch as an epichlorohydrin rubber, nitrile rubber, acrylic rubber,urethane rubber and chloroprene rubber, or further a compositionprepared by mixing a low resistive substance such as an electricallyconductive powder (carbon black, metal powder and the like ),electrically conductive fiber (carbon fiber and the like),fluorine-containing surfactant and ester type plasticizer into a highlyresistive synthetic rubber such as a silicone rubber, ethylene propylenerubber, styrenebutadiene rubber, or a fluorine-containing polymer suchas a fluorine-containing resin and fluorine-containing rubber.

However in the semi-electrically conductive roller having theelectrically resistive layer as mentioned above, when the resistivelayer comprises a polar rubber such as a epichlorohydrine rubber,nitrile rubber and acrylic rubber, since a releasing property against atoner is generally poor, there is a problem that a small amount of thetoner remaining on the surface of the photoreceptor sticks to the rollersurface and is solidified (This phenomenon is called a toner filming.)when this roller is used as a charging roller and a transferring roller.For instance, in case where the toner is solidified on the chargingroller, a roller charger is deprived of its function, and it becomesimpossible for the portion of the roller, where the toner sticks and issolidified, to electrically charge the photoreceptor. Also when used asthe developing roller, there occurs more remarkably the sticking of thetoner to the roller surface, which becomes a cause for an irregularimage and is not preferable.

Also in case where the materials of the electrically resistive layer areones prepared by dispersing a carbon black or the like in a syntheticrubber or a fluorine-containing polymer, there is a disadvantage that anelectric breakdown is liable to occur under high voltage. For instance,in case of the charging roller, if there are pin holes on the surface ofthe photoreceptor, there is formed an electrically conductive passleading to a back plate of the photoreceptor, thus excess current flowsfrom the charging roller and a voltage applied to the charging rollerdrops. From a point of an image, in a negative-positive phenomenon,there is a problem that a black line appears in the horizontal directionof a contacting portion between the photoreceptor and the chargingroller.

This occurs due to the reason mentioned hereinbelow. As mentioned above,when adding the carbon black to the insulative substrate, the volumespecific resistance of the obtained composite material sharply changesfrom not less than 10¹² Ωcm down to not more than 10⁶ Ωcm when thecarbon black to be added exceeds a certain amount. Therefore if thedispersion of carbon black is insufficient, there occurs locally adifference in an adding amount and there is a portion where the volumespecific resistance is not more than 10⁶ Ωcm. In this portion thereoccurs an electric breakdown arising from an insufficient dispersion ofthe carbon black.

Also when a fluorine-containing surfactant and an ester type plasticizerare added to the materials of the electrically resistive layer, theseadditives bleed out with the lapse of time. Thus not only an initialcharacteristic of the roller cannot be maintained for a long period oftime, but also the surface of the photoreceptor is stained and a life ofa whole system is also shortened.

An object of the present invention is to provide a composition and paintcomposition being capable of imparting electric conductivity andnon-tackifying property to a resin or a rubber.

Also an object of the present invention is to provide asemi-electrically conductive roller being excellent in releasingproperty (non-tackifying property) against a toner and having anelectrically resistive layer, which comprises materials containingneither an electrically conductive powder such as carbon black beingliable to cause an electric breakdown under high voltage nor a lowresistive substance such as a fluorine-containing surfactant and estertype plasticizer being liable to ooze out from the inside of the rollerwith the lapse of time and stain the photoreceptor and the like.

DISCLOSURE OF THE INVENTION

This invention relates to a composition being capable of impartingelectric conductivity and non-tackifying property and comprising (A) acarbon fluoride having a fluorine atom to carbon atom ratio F/C of morethan 0.5 and less than 1.0 and (B) at least one kind selected from thegroup consisting of a thermoplastic resin, a thermosetting resin and arubber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustrative view of an electrostatic copying machinewherein the semi-electrically conductive roller of the present inventionis used as a charging roller.

FIG. 2 is an outline cross-sectional view showing a layer configurationof the semi-electrically conductive roller of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

It is preferable in the component (A) comprising such a composition thatthe F/C is more than 0.5 and less than 1.0, preferably not more than0.95, particularly not more than 0.9. It is preferable that the carbonfluoride of the component (A) is one obtained by fluorinating the carbonblack, particularly electrically conductive carbon black with a fluorinegas. The fluorinating temperature is preferably 200° to 600° C.

Also in the component (B), as the thermoplastic resin, afluorine-containing resin, polyamide or polyamideimide is preferable,and as the thermosetting resin, a silicone resin is preferable.

As the rubber, a silicone rubber or fluorine-containing rubber, or astyrene-butadiene rubber, polyurethane rubber, nitrile rubber,chloroprene rubber or EPDM is preferable.

The mixing ratio (A)/(B) of the component (A) to the component (B) ispreferably 1/99 to 30/70 in a weight ratio.

The present invention further relates to a paint composition comprisingthese compositions and a liquid carrier.

The present invention still further relates to an electricallyconductive non-tackifying roller comprising an electrically conductiveelastic layer having a volume specific resistance of not more than 10⁵Ωcm and an electrically resistive layer having a volume specificresistance ranging from 10⁶ to 10¹² Ωcm, both of which are formed on anelectrically conductive supporting body at least in that order, and theresistive layer comprises the above-mentioned compositions.

Such a roller is suitable for the semi-electrically conductive rollerssuch as the charging roller, transferring roller and developing rollerfor the electrostatic copying machine, and particularly a roller whereinthe electrically resistive layer is the outermost layer or a roller ofwhich volume specific resistance of the resistive layer is from 10⁸ to10¹² Ωcm is desirable.

The composition of the present invention being capable of imparting anelectric conductivity and non-tackifying property comprises (A) a carbonfluoride having a fluorine atom to carbon atom ratio F/C of more than0.5 and less than 1.0 and (B) at least one selected from the groupconsisting of a thermoplastic resin, a thermosetting resin and a rubber.

When the F/C of the carbon fluoride of the component (A) is not morethan 0.5 (fluorine content of not more than 44.2% by weight ), effect ofthe fluorination is insufficient, and there remain problems inherent tocarbon materials before the fluorination as they are, that is to say,problem such that a rate of change of a resistance by the mixing amountis very large and a control of electric conductivity is difficult, andthat due to the developed structure, dispersion of the carbon fluoridebecomes nonhomogeneous and the obtained composition becomes hard. Whenthe F/C is not less than 1.0 (fluorine content of not less than 61.4% byweight), an intended electric conductivity cannot be imparted to thecomposition. The preferable F/C is more than 0.5 and not more than 0.95(fluorine content of 60% by weight), particularly more than 0.5 and notmore than 0.9 (fluorine content of 58.8% by weight).

In the present invention, the fluorine content is measured in thefollowing manner. The carbon fluoride is packed together with acombustion improver Na₂ O₂ and polyethylene film and is burned in asealed flask filled with oxygen. The produced hydrogen fluoride ismeasured with a fluoride ion specific electrode ion meter (Ion Analyzer901 of Orion Corp.) by a usual method. The fluorine content iscalculated from the obtained value. By using the obtained fluorinecontent, the F/C is caluculated.

Such a carbon fluoride (A) comprises a poly(carbon monofluoride) as amain component, and preferable is one obtained by fluorinating a carbonmaterial having an average particle size of not more than 1 μm,preferably not more than 0.1 μm with a fluorine gas. In the carbonfluoride to be obtained from carbon materials having an average particlesize exceeding 1 μm, for example, petroleum cokes, graphite powder,carbon fiber and the like, its mount have to be increased to impartelectric conductivity and non-tackifying property to a resin or arubber, and there is a tendency that there occur disadvantages such asincreased surface roughness, deterioration of mechanical strength,uneven resistivity, and the like of the obtained composition.

The carbon material suitable for the carbon fluoride (A) is a carbonblack having the above-mentioned average particle size. As the carbonblack, there are used ones commercially available, for example, furnaceblack for rubbers (for example, Asahi #55 and the like made by AsahiCarbon Kabushiki Kaisha), channel black for color (for example, Leben7000 made by Columbia Carbon Co., Ltd. ), thermal black (Sevacarbo MT-C1made by Columbia Carbon Co., Ltd.) and the like.

Among the carbon blacks, ones particularly generally called anelectrically conductive carbon black are preferable. The electricallyconductive carbon black is defined using such factors that an averageparticle size is small (average particle size not more than 0.1 μm), asurface area is large (N₂ surface area not less than 50 m² /g), astructure is progressed (oil absorption amount not less than 100 cc/g),impurities content is small (ash content less than 0.1%) and forminginto graphite is advanced. Because the electrically conductive carbonblack can impart electric conductivity to materials in a relativelysmall mixing amount, it is used widely. Example thereof are onescommercially available, for instance, Ketchen Black EC and Ketchen BlackEC-600JD (available from Ketchen Black International Kabushiki Kaihsa),Black Purples 2000, Vulcan XC-72 and CSX-99 (available from CablackKabushiki Kaisha), Denka Black (available from Denki Kagaku KogyoKabushiki Kaisha), Conductex 950 (available from Columbia CarbonKabushiki Kaisha) and the like.

The carbon fluorides (A) to be used in the present invention areobtained by bringing the mentioned carbon materials into contact with afluorine gas at a temperature ranging from 200° to 600° C., morepreferably from 300° to 500° C. At a reaction temperature lower thanthis range, there occur problems that the fluorination reaction advancesslowly, the fluorination degree is difficult to increase, thermalstability is not sufficient and properties inherent to carbon fluoridessuch as non-tackifying property and lubricity are not exhibited.Reversely when the reaction temeperature is higher than this range,thermal decomposition reaction is easy to occur and a yield of theobtained carbon fluorides lowers. Also there are some cases where suddenand sharp thermal cracking reaction occurs resulting in an explosion.Therefore it is necessary to fully pay attention to it.

The fluorine gas to be used for the reaction may be diluted with inertgases such as nitrogen, argon, helium and tetrafluorocarbon and maycontain hydrogen fluoride. Also the reaction can be carried out atnormal pressure, and there is no problem if the reaction is conductedunder reduced pressure or under pressure.

Besides the above-mentioned conditions, the reaction time, fluorine gasflow and the like may be properly adjusted depending on reactivity ofthe carbon materials as raw materials with the fluorine gas and thedesired F/C (fluorine content).

As the resin or rubber for the component (B), there are thermoplasticresins, thermosetting or rubbers.

The thermoplastic resins can be used advantageously as the materialsbeing high in processability since they can be plastically deformable byheating after once formed into a molded article. For example, there is afluorine-containing resin, polyamide, polyamideimide, polyacetal or thelike.

Examples of the fluorine-containing resins are polytetrafluoroethylene;copolymers of tetrafluoroetylene with at least one of othercopolymerizable ethylenically unsaturated monomer (for example, olefinssuch as ethylene and propylene, halogenated olefins such ashexafluoropropylene, vinylidene fluoride, chlorotrifluoroethylene andvinyl fluoride, and perfluoroalkyl vinyl ethers);polychloro-trifluoroethylene; polyvinylidene flouride; and the like.Particularly preferable flourine-contining resins arepolytetrafluoroethylene, copolymers of tetrafluoroethylene with at leastone of hexafluoropropylene, perfluoro(methyl vinyl ether),perfluoro(ethyl vinyl ether) and perfluoro(propyl vinyl ether)(containing generally in an amount of not more than 40% by mole withrespect to tetrafluoroethylene), and the like. When thefluorine-containing resin is used, there is exhibited an effect suchthat a composition having an excellent heat resistance, non-tackifyingproperty, water-and oil-repelling property, lubricity and chemicalresistance as compared with resins for general uses can be obtained.

As the polyamides, there can be used various materials commerciallyavailable as nylon resins. For example, there are 6 nylon, 66 nylon, 610nylon, 612 nylon, 11 nylon, 12 nylon, 46 nylon and the like. Alsoaramide wherein an aromatic component is introduced in a main chain, isencompassed therein. As the aramide, there are poly(paraphenyleneterephthalamine) and the like. These, though relatively inexpensive,exhibit effects such as an excellent heat resistance, high mechanicalstrength and excellent lubricity.

As the polyamideimide, there is, for example, Toron (available fromMitsubishi Kasei Kogyo Kabushiki Kaisha) obtained by the reaction oftrimellitic anhydride and aromatic diamine, and the like, which exhibitseffects such as a very high mechanical strength and heat resistance.

When the thermosetting resins are used, since they have athree-dimensional structure after being cured, they can allow propertiessuch as heat resistance, weatherability and chemical resistance and canbe used advantageously mainly as the paint composition. For example,there are silicone resins, phenol resins and the like.

As the silicone resins, there can be, for example, polymers generallycalled the silicone resins having a three-dimensional network structureand being obtained by hydrolyzing organosilane. As the commerciallyavailable ones, there are, for example, SR 2400 (available from TorayDow Corning Silicone Kabushiki Kaisha) and the like. Also there are onesbeing copolymerized with another organic resin generally called thesilicone modified resin. There are silicone alkyd resin, siliconepolyester resin, silicone epoxy resin and the like, depending on thekinds of organic resins to be copolymerized. As the commerciallyavailable resins, there are, for example, SR2100, SR2108, SR2115 (allavailable from Toray Dow Corning Silicone Kabushiki Kaisha) and the likewhich exhibit effect that low temperature curing is possible atrelatively low cost.

When the rubbers are used, because of elasticity of them, thecomposition can be endowed with property to be deformed by a smallstress and restored to the original state, and can be usedadvantageously as the materials for sealants, adhesives and rollers.Examples of the rubbers are ones for general uses, such as a siliconerubber or a fluorine-containing rubber, a styrene-butadiene rubber, apolyurethane rubber, a nitrile rubber, a chloroprene rubber, EPDM or thelike.

As the silicone rubbers, there are various materials commerciallyavailable for sealants, coatings, formation of die and the like.

The silicone rubbers are generally classified into various grades,depending on their states and curing mechanisms, and are roughlyclassified into Mirable type silicone rubber and liquid form siliconerubber. The Mirable type silicone rubber is of a type heat-curing byadding a vulcanizing agent during the use, and is molded and processedin the same manner as in general organic rubbers. The Mirable typesilicone rubbers are used as materials for key pats of desk-topcalculators and the like and also rollers for an electrostatic copyingmachine. The liquid form silicone rubbers are in the form of a liquidhaving low density and requires no specific curing device. They arecured and formed into rubbers at room temperature or by heating, and arefeatured by excellent workability. There are two types of liquid formsilicone rubbers, one component type and two component type, and as thecuring types, they are classified into a condensation type and anaddition type. The liquid form silicone rubbers are widely used asadhesives, sealants, coatings, potting agents and the like.

Both the Mirable type and liquid form silicone rubbers exhibit effectssuch as excellent electrical property as well as excellent heatresistance and cold resistance, good compression restoration property,chemical resistance, oil resistance and weatherability in a widetemperature range.

The fluorine-containing rubber is a highly fluorinated elasticcopolymer, and particularly preferable fluorine-containing rubbers areelastic copolymers of generally 40 to 85% by mole of vinylidene fluoridewith at least one of other copolymerizable fluorine-containingethylenically unsaturated monomers. The fluorine-containing rubber whichcontains iodide in the polymer chain also is, for instance, afluorine-containing rubber which maininly comprises an elastic copolymerof the same % by mole as mentioned above of vinylidene fluoride with atleast one of other copolymerizable fluorine-containing ethylenicallyunsaturated monomers, said copolymer being containing 0.001 to 10% byweight, preferably 0.01 to 5% by weight of iodide at its polymer end(JP-A-40543/1977). Typical examples of the other ethylenicallyunsaturated monomers which are copolymerized with vinylidene fluoride toprovide the elastic copolymers are hexafluoropropylene,pentafluoropropylene, trifluoroethylene, trifluorochloroethylene,tetrafluoroethylene, vinyl fluoride, perfluoro(methyl vinyl ether),perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), and thelike. Particularly preferable fluorine-containing rubbers are vinylidenefluoride/hexafluoropropylene elastic copolymer and vinylidenefluoride/tetrafluoroetylene/hexafluoropropylene elastic copolymer. Theuse of the fluorine-containing rubbers gives effects such as excellentheat resistance and chemical resistance.

When the above-mentioned rubbers for general purposes are used, heatresistance, chemical resistance and the like are poor as compared withthe fluorine-containing rubbers, but a flexibility is easy to obtain andcost is low.

The mixing ratio of the components (A) to (B) is 1/99 to 30/70 (weightratio, hereinafter the same), preferably 5/95 to 20/80, particularlypreferably 5/95 to 15/85. If the mixing amount of the component (A)becomes small, sufficient effect of adding the carbon fluorides is notobtained, and if it becomes too much, mechanical strength such astensile strength tends to lower.

Additives to be usually used may be added to the composition of thepresent invention if necessary. As such additives, there are, forexample, a vulcanizing agent, vulcanization accelerator, vulcanizingauxiliary, inorganic filler, releasing agent and the like. The mixingamount of the additives is not more than 20 parts by weight, preferablynot more than 15 parts by weight based on 100 parts by weight of thecomponent (B). Also in order to enhance abrasion resistance, lowmolecular weight polytetrafluoroethylene can be added in an amount up to20 parts by weight.

The composition of the present invention is mixed and prepared by theusual method such as the follwoing method.

(1) In case where the component (B) is a resin,

A resin, carbon fluoride and, if necessary, various additives are mixedin a mixer such as a V type blender, tumbler and Henshel mixer andfurther mixed in a melt kneader such as a double screw extruder to beformed into pellets. The thus obtained pellets are made into the desiredform of moldings, for example, plate, film and the like by the use of amolding machine being usually used for molding a thermoplastic resin,for example, an injection molding machine, compression molding machine,extrusion molding machine and the like.

(2) In case where the component (B) is a rubber,

A carbon fluoride and, if necessary, various additives are added to arubber composition for vulcanization in the form of a solid, and mixedby the use of, for example, a banbury mixer or a rubber roll to forminto a homogeneous rubber composition for the vulcanization. Also asanother mixing method of these additives, there is a method to pre-mixthem with the rubber by a usual open roll and kneader and then mix withother components.

The composition of the present invention which is capable of impartingelectric conductivity and non-tackifying property can be applied foruses such as paint compositions, elastomer materials for sealing beingsuitable for semiconductor production industries, auto parts such asfuel tubes and the like, and further can be used for electricallyresistive layers of semi-electrically conductive rollers forelectrostatic copying.

Also in case where fluorine-containing rubbers are sued as the component(B), electrically conductive non-tackifying vulcanized rubbers can beprovided. The best mode in this case is explained below.

The carbon fluoride of the component (A) is mixed homogeneously with afluorine-containing rubber composition for the vulcanization by usualmixing method of a fluorine-containing rubber composition for thevulcanization, for example, with a banbury mixer, rubber roll or thelike. Also as another mixing method of these additives, there is amethod to pre-mix them with the fluorine-containing rubber by a usualopen roll and kneader and then mix with other components.

The thus homogeneously mixed fluorine-containing rubber composition issubjected to the vulcanization and molding as it is, and also can beused as a composition in the form of a liquid being dispersed ordissolved properly in water or organic solvent.

This liquid composition can be used for the purpose of the presentinvention, being impregnated or coated onto paper, fiber cloth, film,sheet, plate, tube, pipe, container and other molded articles (Materialsof them to be used are synthetic resin, rubber (including afluorine-rubber), metal, ceramic and the like) to be vulcanized anddeposited.

As the organic solvents, there can be used methyl ethyl ketone, acetone,cyclohexanone, amyl acetate, dioxane, tetrahydrofuran alone or incombination of not less than two kinds thereof.

As mentioned above, the fluorine-containing rubber composition of thepresent invention can be vulcanized under usual conditions in accordancewith the known method for vulcanizing a fluorine-containing rubber, andthe intended vulcanized rubber having electric conductivity andnon-tackifying property is obtained without impairing various propertiesinherent to rubbers.

The present invention further relates to a paint composition comprisingthe above-mentioned electrically conductive and non-tackifying compoundand a liquid carrier.

The liquid carrier is mixed since it is suitable for various paintingworks such as spray coating, brush coating and dip coating. Examplesthereof are, for instance, lower ketones such as acetone, methyl ethylketone and cyclohexanone; lower esters such as ethyl acetate, propylacetate, and butyl acetate; cyclic ethers such as tetrahydrofuran and1,4-dioxane; water; a mixture of water with alcohols such as methanol,ethanol and isopropyl alcohol, glycols such as ethylene glycol and watersoluble organic liquid such as methyl cellosolve; and not less than twokinds thereof. Particularly preferable liquid carrier is one comprisingwater as a main component from the viewpoint of painting workability,storage stability, protection of global environment and the like.

The content of the electrically conductive non-tackifying composition inthe paint composition of the present invention may be properly selectedin consideration of painting workability, film forming property and thelike, and is generally 10 to 70% by weight, preferably 30 to 60% byweight.

Further additives which are usually mixed in various paints, may beadded depending on uses. As these additives, there are, for example,pigments, adhesion enhancing agents (organic resin powder and the like),lubricity imparting agents (fluorine-containing oil and the like),abrasion resistance enhancing agents (inorganic ceramic powder and thelike), thickness, film forming agents, surfactants and the like. Themixing mounts of them may be suitably selected depending on uses,coating methods and the like. Attention is to be paid not to impair theintended electric conductivity and non-tackifying property of thepresent invention.

Then explanation is made on a fluorine-containing rubber paint in casewhere a fluorine-containing rubber is used as the component (B) of theelectrically conductive non-tackifying composition.

The liquid carrier to be used is selected from the above-mentionedorganic solvents such as lower ketone, lower ester and cyclic ether,water and a mixture of water and water soluble organic liquid. As thewater soluble organic liquid, there are alcohols. Among these liquidcarriers, water and one comprising water as a main component are mostpreferable from a point that no painting workability is impaired.

Inorganic fibrous substances as the other substances being contained inthe flourine-containing rubber paints are used to enhance compressionrestoration property of a flurine-containing rubber coating. As thetypical substances, there are glass fibers, carbon fibers, asbestosfibers, potassium titanate fibers, and the like. It is desirable that anaverage length of this inorganic fibrous substance is at least 1 μm,preferably 1 to 100 μm.

Amine compounds to be added, if desired, in the fluorine-containingrubber paint are intended to function mainly as the vulcanizing agent ofthe fluorine-containing rubber and improve mechanical property togetherwith the above-mentioned coupling agent. Typical examples of suchcompounds are mono-amines such as ethyl amine, propyl amine, butylamine, benzyl amine, allylamine, n-amyl amine and ethanolamine, diaminessuch as ethylenediamine, trimethylenediamine, tetramethylenediamine,hexamethylenediamine and 3,9-bis(3-aminopropyl)-2,48,10-tetraoxaspiro[5,5]undecane and polyamines such asdiethylenetriamine, triethylenetetramine, tetraethylenepentamine andpentaethylenehexamine. Particularly amine compounds having two or moreof terminal amino groups are preferable.

The fluorine-containing rubber paints are made homogeneous by usuallymixing an electrically conductive substance, pigment, acid receivingagent, filler and the like (in addition, surfactant may be used ifnecessary) with a mixture of a fluorine-containing rubber,fluorine-containing resin and liquid carrier, adding a coupling agentand, if necessary, amine compound (if necessary, the above-mentionedadditives such as pigment, acid receiving agent and filler may be added)to the obtained dispersion solution, and them mixing sufficiently byusual method.

The weight ratio of the fluorine-containing rubber to thefluorine-containing resin is desirably 95:5 to 35:65. When the ratio ofthe fluorine-containing resin is lower than the above-mentioned lowerlimit, the intended improvement of non-tackifying property and lubricityis not sufficient. On the contray, when higher than the mentioned upperlimit, the intended coating thickness cannot be obtained and cracks andpin holes are easy to occur on the coating.

The adding amount of the carbon fluoride of the component (A) can bechanged depending on uses of paints and kinds of electrically conductivesubstances. The carbon fluoride may be added so that the volume specificresistance of the fluorine-containing rubber coating is not more than10⁸ Ωcm for the purpose to prevent charging, and not more than 10² Ωcmin case of using as a plate heater.

The coupling agent is usually added in an amount of 1 to 50 parts byweight, preferably 1 to 20 parts by weight based on 100 parts by weightof a fluorine-containing rubber. In case where an amine compound isdesired to be added, the amine compound and coupling agent are mixed sothat a total amount of them becomes the value mentioned above. In thiscase, the molar ratio of the coupling agent to the amine compound isselected from the range of 1:99 to 99:1.

As the above-mentioned acid receiving agent, there is used one usuallyused for the vulcanization of fluorine-containing rubbers in the samemanner. For example, one or two or more kinds of bivalent metal oxidesor hydroxides are used. Concretely there are oxides or hydroxides ofmagnesium, calcium, zinc, lead and the like. Also as the above-mentionedfiller, there are used silica, day, diatom earth, talc, carbon and thelike.

The fluorine-containing paints are coated or impregnated onto thesubstrate by usual coating methods (brush coating, dipping, spraying andthe like), and the intended fluorine-containing rubber coating can beobtained by curing under a temperature condition of room temperature to400° C., preferably 100° to 400° C. for a suitable period of time.

Coating thickness of the fluorine-containing rubber paints is preferablynot less than 5 μm. If the coating thickness is less than 5 μm, there isa fear that uneveness occurs on the whole surface of the substrate andthere occurs uncoated part. The thus obtained fluorine-containing rubbercoating has electric conductivity in addition to properties inherent tofluorine-containing rubbers such as heat resistance, weatherability,abrasion resistance, oil resistance, solvent resistance and chemicalresistance, and is excellent in adhesivity to the substrate andmechanical property of the coating itself and is further endowed withnon-tackifying property and lubricity on the coating surface.

The coupling agent is a compound acting on an interface between theorganic material and the inorganic material and forming a more rigidbridge between both the materials rather than chemical or physicalbonding. The coupling agent is usually a compound of silicon, titanium,zirconium, hafnium, trium, tin, aluminum or magnesium, and a compoundhaving a group being capable of bonding the oraganic and inorganicmaterials. Among these coupling agents, preferable is silane couplingagent, and ortho-acid esters of transition elements of the group IV ofthe periodic table (for example, titanium, zirconium and the like) andtheir derivatives. Particularly an aminosilane compound is mostpreferable.

As the silane coupling agents, there can be, for example, silanecompounds shown by the formula:

    R.sup.1 ·Si·R.sup.2.sub.3-a ·R.sup.3.sub.a

(wherein, R¹ is an alkyl group or a vinyl group having 1 to 10 carbonatoms and at least one kind functional atom or group selected fromchlorine atom, amino, aminoalkyl, ureide, glycidoxy, epoxy cyclohexyl,acryloyloxy, methacryloyloxy, mercapto and vinyl, R² and R³ arerespectively an atom or group selected from chlorine atom, hydroxyl,alkoxyl having 1 to 10 carbon atoms, alkoxy-substituted alkoxyl having 2to 15 carbon atoms, hydroxyalkyloxyl having 2 to 4 carbon atoms andacyloxyl having 2 to 15 carbon atoms, a is 0,1 or 2).

R¹ is an alkyl group having a functional substituent, and suitableexamples thereof are β-aminoethyl, γ-aminopropyl,N-(β-aminoethyl)-γ-aminopropyl, γ-ureidopropyl, γ-glycidooxypropyl,β-(3,4-epoxycyclohexyl)ethyl, γ-acryloyloxypropyl,γ-methacryloyloxypropyl, γ-mercaptopropyl, β-chloroethyl,γ-chloropropyl, γ-vinylpropyl and the like. Also R¹ may be a vinylgroup.

Examples of the above-mentioned silane compounds to be suitably usedare, for instance, γ-aminopropyltriethoxysilane,N-β-aminoethyl-γ-aminopropyltriethoxysilane,γ-ureidopropyltrietholxysilane, γ-glycidoxypropyltrimethoxysilaneβ-(3,4-epoxycylohexyl)ethyltrimethylsilane,γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane,γ-chloropropyltrimethoxysilane, vinyltris (β-methoxyethoxy)silane,vinyltriethoxysilane, vinyltrichlorosilane, vinyltriacetoxysilane,N-(trimethoxysilylpropyl) ethylenediamine,N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane andβ-aminoethyl-γ-aminoethyl-γ-aminopropyltrimethoxysilane. Among thesesilane coupling agents, aminosilane compounds, for example,γ-aminopropyltriethoxysilane, N-β-aminoethylγ-aminopropyltrimethoxysilane, N-(trimethoxysilylpropyl)ethylenediamine, N-β-aminoethyl-γ-aminopropyl-γ-methyldimethoxysilane,γ-ureidopropyltriethoxysilane,β-aminoethyl-β-aminoethyl-γ-aminopropyltrimethoxysilane and the like areparticularly preferable, because they function as the vulcanizing agentsfor the fluorine-containing rubbers, contribute to enhance adhesivity tothe substrate, and further are used safely against the liquid carrier.

As the compounds of titanium, zirconium, hafnium and trium, there can bementioned, for example, ortho esters shown by the formula:

    T(OR).sub.4

(wherein, T is titanium, zirconium, hafnium or trium, R shows alkyl,cycloalkyl or allyl) and derivatives to be obtained by reacting themwith one or more compounds having at least one functional group. As theabove-mentioned compounds having at least one functional group, therecan be used polyhydric alcohols such as glycerine, ethylene glycol,1,3-butanediol, 2,3-butanediol, hexylene glycol and octylene glycol,oxyaldehydes such as salicylaldehyde and glycose, oxyketones such asdiacetone alcohol and fructose, oxycarbonic acids such as glycolic acid,lactic acid, dioxy maleic acid and citric acid, diketones such asdiacetylacetone, ketones such as acetoacetate, esters of ketonic acidssuch as acetoacetic ethyl, oxyamines such as triethanolamine anddiethanolamine, and oxyphenol compounds such as cathecol and pyrogallol.

Concrete examples of the compounds in case where T is titanium, aretetraalkylti tanate (for example, tetraethyl titanate, tetraisopropyltitanate and tetrabutyl titanate), tetraethyleneglycol titanate,triethanolamine titanate, titanium acetylacetonate, isopropyltrioctanoyltitanate, isopropyl trimethacryl titanate, isopropyltriacryl titanate,isopropyltri(butyl, methylpyrophosphate) titanate, tetraisopropyldi(dilaurylphosphire) titanate, dimethacryloxy acetate titanate,di(dioctylphosphate) ethylene titanate and the like.

As the zirconium compounds, there can be used the same compounds as theabove-mentioned titanium compounds. Examples thereof are tetraalkylzirconate such as tetraethyl zirconate and tetrabutyl zirconate,n-propyl zirconate, isopropyl zirconate, n-butyl zirconate, isobutylzirconate, zirconium acetylacetonate and the like.

As the compounds of hafnium and trium, there can be used the samecompounds as the titanium and zirconium compounds.

As the tin compounds, there can be used organic or inorganic compounds,for example, SnCl₄ and the like. As the aluminum compounds, there can bementioned aluminum isopropylate, monosec-butoxyaluminum diisopropylate,aluminumsec-butylate, ethylacetoacetate aluminum diisopropylate,aluminumtris (ethylacetoacetate) and the like.

As the magnesium compounds, there can be mentioned magnesium alcoholatessuch as magnesium methylate and magnesium ethylate.

The electric conductivity of the above-mentioned fluorine containingrubber paint has a feature that the resistivity can be easily controlledto be a desired value by selecting the kind of the carbon fluoride to bemixed, fluorine content and mixing amount.

Also this fluorine-containing rubber paint has a feature that by itsexcellent dispersibility as the paint and a little increase in paintviscosity, coating is easy and as a result, a coating having uniformproperty can be obtained.

The fluorine-containing rubber paint of the present invention can beused for various uses requiring a non-tackifying and electricallyconductive coating, for example, electrical parts such as electricallyconductive packing, pin hole tester detecting element, measuringelectrode, and those for prevention of high frequency interference,alternative for solder, printing circuit board, condenser, fixed orvariable resistor, measuring electrodes such as piezoelectric andphotoelectric elements, seal for electronic devices, prevention ofcharging of powder mill, factories generating dusts, operation room andbelt for belt conveyer, prevention of charging of sub-heater forthermostat, resistance wire, spot welder, non-electrically conductiveplating and rubber-or resin-made various rolls, plate heater and thelike. This paint is particularly suitable of semi-electricallyconductive rollers of electrostatic copying machine, and concretely canbe used for the production of a charging roller, transferring roller,developing roller and fixing roller (soft type), press roller (backuproller), paper feed roller and the like.

The fluorine-containing rubber paint is as referred to hereinabove, andalso can be produced in the same manner when other resins or rubbers areused as the component (B).

Mentioned below are descriptions relating to only characteristic mattersof each resin and rubber. Other technical matters and conditions aresubstantially the same as those of the fluorine-containing rubber paint,and it is possible to make a design change obvious to a person skilledin the art.

Explained below is the case where a fluorine-containing resin is used asthe component (B).

Examples of the fluorine-containing resins are polytetrafluoroethylene;copolymers of tetrafluoroetylene with at least one of othercopolymerizable ethylenically unsaturated monomer (for example, olefinssuch as ethylene and propylene, halogenated olefins such ashexafluoropropylene, vinylidene fluoride, chlorotrifluoroethylene andvinyl fluoride, and perfluoroalkyl vinyl ethers);polychloro-trifluoroethylene; polyvinylidene flouride; and the like.Particularly preferable flourine-containing resins arepolytetrafluoroethylene, copolymers of tetrafluoroethylene with at leastone of hexafluoropropylene, perfluoro(methyl vinyl ether),perfluoro(ethyl vinyl ether) and perfluoro(propyl vinyl ether)(containing generally in an amount of not more than 40% by mole withrespect to tetrafluoroethylene), and the like.

The liquid carrier is mixed since it is suitable for various paintingworks such as spray coating, brush coating and dip coating. Examplesthereof are, for instance, lower ketones such as acetone, methyl ethylketone and cyclohexanone; lower esters such as ethyl acetate, propylacetate, and butyl acetate; cyclic ethers such as tetrahydrofuran and1,4-dioxane; water; a mixture of water with alcohols such as methanol,ethanol and isopropyl alcohol, glycols such as ethylene glycol and watersoluble organic liquid such as methyl cellosolve; and not less than twokinds thereof. Particularly preferable liquid carrier is one comprisingwater as a main component from the viewpoint of painting workability,storage stability, protection of global environment and the like.

In addition, surfactants, pigments, fillers and various paintingadditives can be added if necessary.

Further additives which are usually mixed in various paints, may beadded depending on uses. As these additives, there are, for example,pigments, adhesion enhancing agents (organic resin powder and the like),lubricity imparting agents (fluorine-containing oil and the like),abrasion resistance enhancing agents (inorganic ceramic powder and thelike), thickness, film forming agents, surfactants and the like. Themixing amounts of them may be suitably selected depeniding on uses,coating methods and the like. Attention is to be paid not to impair theintended electric conductivity and non-tackifying property of thepresent invention.

The adding amount of the carbon fluoride of the component (A) can bechanged depending on uses of paints, a kind of the carbon fluoride andthe degree of the fluorination. The carbon fluoride may be added so thatthe volume specific resistance is not more than 10⁸ Ωcm for the purposeto prevent electric charging.

The fluorine-containing resin paint of the present invention can be usedfor paints for a fixing roll (hard type) of an electrostatic copyingmachine, coating for prevention of electric charging of resin-madeparts, non-tackifying (stainproof) coating of metals, coating fornon-lubricant processing of metals (lubricated steel plate) and thelike.

In case where polyamides are used as the component (B), paints can beprepared in the same manner as in the above-mentionedfluorine-containing resin. Also it is possible to previously combine thecarbon fluoride of the component (A) with fine particles of polyamide bya dry method to give composite fine particle materials and then dispersethem in the liquid carrier by a proper method. As the polyamide fineparticles to be used in this case, there can be mentioned fine particlesof a spherical form, for example, SP-500 (available from Toray KabushikiKaisha). For the combining method, for example, Hybridizer (availablefrom Kabushiki Kaisha Nara Kikai Seisakusho), Mechanomill (availablefrom Okada Seiko Kabushiki Kaisha) and the like can be used. The featureof this method is such that since composite fine particle materials arepreviously prepared, they are mixed homogeneously, and a uniform coatingis easily obtained irrespective of paints being in a dispersed state.

As the uses, this paint is suitable for fields wherein mechanicalstrength and abrasion resistance are required though heat resistance,chemical resistance and non-tackifying property may be inferior ascompared with fluorine-containing resin paints. For example, it ispossible to use for coating of semi-electrically conductive rollers ofan electrostatic copying machine, coating for non-lubricant processingof metals, coating for preventing electric charging of variousresin-made parts and the like.

Also in case where polyamideimides are used as the component (B), in thesame manner as in case of the above-mentioned fluorine-containing resinsand polyamides, the polyamideimides not only are used alone, but alsoare mixed with flourine-containing resins for use as a primer paint fora fluorine-containing resin paint or are mixed with thermoplastic resinssuch as polyamides to improve mechanical property.

In case where silicone resins or silicone rubbers are used as thecomponent (B), an organic solvent mainly such as toluene or silicone oilhaving a low boiling point is used as the liquid carrier. The carbonfluoride as the component (A) is added together with a catalyst (forexample, zinc octylate) and various additives to a commerciallyavailable composition for curing (for example, SR-2400, available fromToray Dow Corning International Kabushiki Kaisha), and fully dispersedin triple rolls and the like. The solvent such as toluene is added togive a paint having a viscosity conforming to a coating method. Afterthe painting, the paint is cured at a specified temperature (forexample, 235° C., for 1 hour).

With regard to rubbers for general uses, the mixing can be carried outin compliance with properties of each rubber in the same manner as inthe above-mentioned fluorine-containing rubber and silicone rubber.

The present invention also further relates to an electrically conductivenon-tackifying roller comprising an electrically conductive elasticlayer having a volume specific resistance of not more than 10⁵ Ωcm andan electrically resistive layer having a volume specific resistanceranging from 10⁶ to 10¹² Ωcm, preferably from 10⁸ to 10¹² Ωcm, both ofwhich are formed at least in that order on an electrically conductivesupporting body, and the electrically resistive layer comprises theabove-mentioned electrically conductive non-tackifying compositions.

Also, for the simplification of the machine, the electrically resistivelayer can be formed directly to the above-mentioned electricallyconductive supporting body such as a metal core roll without forming theelectrically conductive elastic layer on the supporting body. In thiscase, it is preferable to make the resistive layer thickness thickenough and make the layer to have a rubber elasticity. In case of afixing process, if an elastic layer is used on the press roller, thefixing roller comprising only an electrically resistive layer free ofelasticity can also be used.

Such a roller is particularly useful semi-electrically conductive rollersuch as the charging roller, fixing roller and developing roller of theelectrostatic copying machine.

In the roller to be used in the present invention, the electricallyconductive elastic layer is first formed on the electrically conductivesupporting body. Materials of this electrically conductive elastic layeris not particularly limited, and this layer comprises a compositionprepared by mixing electrically conductive powder and fiber (carbonblack, metal powder, carbon fiber and the like) in a synthetic rubbersuch as silicone rubber, ethylene propylene rubber, epichlorohydrinerubber, nitrile rubber and urethane rubber. This layer has a volumespecific resistance of not more than 10⁵ Ωcm, preferably not more than10³ Ωcm and a rubber hardness (JIS A) in the range of 20 to 50 degrees,preferably 25 to 40 degrees. It is not preferable to use a plasticizerand surfactant for the purposes of adjusting a resistance and a rubberhardness when mixing the electrically conductive powder and the like.This is because these chemicals bleed out with the lapse of time,resulting in the contamination of the surface of the photoreceptor andthe occurrence of toner filming on the surface of the roller.

The materials of the electrically conductive supporting body are notparticularly limited, and aluminum or an alloy comprising aluminum as amain component or stainless steel can be used.

Then the method for producing the roller of the present invention isexplained below. (i) At first, as the material for the electricallyconductive elastic layer, for instance, a peroxide vulcanizing agent isadded to a rubber compound prepared by dispersing a carbon black in aheat-vulcanizing silicone rubber, and then kneaded sufficiently withtwin rollers to obtain a carbon black-dispersed rubber compound having ahomogeneous composition. (ii) This rubber compound is wound on an outercircumference of a metal core roll, and put in a die for molding theroller which has been preheated (for instance, 170° C.). Then aspecified pressure (for instance, 120 kg/cm²) is applied to carry out afirst vulcanization (for instance, for 10 minutes). (iii) Then thepressure applied to the die is relieved, and the roller is taken out tocarry out a second vulcanization (for instance, 200° C., for 4 hours).(iv) After that, the surface of the roller is polished, and the outsidedimensions are obtained and at the same time, the surface roughness ismade to be not more than 10 μm (Rz). (v) Afterwards the above-mentionedelectrically conductive non-tackifying composition as the material forthe electrically resistive layer is coated on the outer circumference ofthe electrically conductive elastic layer obtained in (iv) with airspray (or dipping method) (coating thickness 30 to 200 μm), andsintering is conducted under the specified conditions (for instance,300° C., for 20 minutes). As the sintering method, in order to minimizeheat deterioration of the electrically conductive elastic layer, it isdesirable to properly use an infrared image oven.

In case where the roller of the present invention is used as thesemi-electrically conductive roller of the electrostatic copyingmachine, it is preferable to use a fluorine-containing polymer such as afluorine-containing resin or fluorine-containing rubber in the component(B) of the electrically conductive non-tackifying composition because ofexcellent non-tackifying property and heat resistance against thetoners, durability and the like.

For example, in case where the electrically resistive layer is formed byadding and dispersing the carbon fluoride (A) in the fluorine-containingpolymer (B), electric conductivity can be controlled by the carbonfluoride, and also an electric breakdown is hard to occur because of anenhanced dispersibility and the deterioration of non-tackifying propertyagainst the toners is solved. Further it is a surprise that abrasionresistance is enhanced as compared with a fluorine-containing polymeralone, and sufficient property as the semi-electrically conductiveroller can be exhibited.

Also when the thermoplastic resins such as polyamide and polyamideimide,thermosetting resins such as a silicone resin, silicone rubbers andrubbers for general uses are used as the component (B) besides thefluorine-containing polymers, they are useful as the electricallyresistive layer of the semi-electrically conductive roller becausenon-tackifying property and lubricity of the carbon fluoride functionadditionally. However among these resins, there are ones having heatresistance and the like being inferior as compared with thefluorine-containing polymer, and therefore for the semi-electricallyconductive rollers produced using these resins, considerations arerequired for the operating conditions and the position where the rollersare used.

The rollers of the present invention are excellent in non-tackifyingproperty against the toners, can prevent the toner filming and canexhibit a stable function as the roller for a long period of time.

The rollers of the present invention can be used on a facsimile, laserprinter and the like besides the electrostatic copying machine.

The present invention is more specifically explained by means ofExamples. Parts mean parts by weight.

EXAMPLE 1

After the mixture of the following components as the electricallyconductive elastic layer was kneaded to give a rubber compound having ahomogeneous composition, the compound was subjected to a firstvulcanization with a die molding (170° C., 10 minutes, 120 kg/cm²), andthen subjected to a second vulcanization (200° C., 4 hours).

    ______________________________________                                        Heat-vulcanizable silicone rubber                                                                         100 parts                                         (DY32-931U: TORAY DOW CORNING SILICONE)                                       Heat-vulcanizable silicone rubber                                                                         100 parts                                         (SRX-557: TORAY DOW CORNING SILICONE)                                         Vulcanizing agent            6 parts                                          (RC-4: TORAY DOW CORNING SILICONE)                                            ______________________________________                                    

The vulcanized article was finished by surface-polishing so as to be asurface roughness of 4 μm (Rz) and an outer diameter of 12 mmφ, and aroller having an electrically conductive elastic layer with a volumespecific resistance of 3×10³ Ωcm on an electrically conductive core rollwas prepared.

To the resulting electrically conductive elastic roller an electricallyconductive non-tackifying composition having the following componentswas applied by air spray method, and then cured at 380° C. for 30minutes to obtain a coating having a thickness of 30 μm.

    ______________________________________                                        Fluorine-containing paint   120 parts                                         (AD-1CR: DAIKIN INDUSTRIES, LTD.,                                             solid content 50%)                                                            Surfactant                   10 parts                                         (HS·208: NIPPON OIL & FATS CO., LTD.)                                Carbon fluoride              3 parts                                          (Starting material: Katzen Black EC                                           (KETZEN BLACK INTERNATIONAL CO., LTD.),                                       F/C: 0.95                                                                     (fluorine content: 60% by weight))                                            Water                        20 parts                                         ______________________________________                                    

As described above, the desired semi-electrically conductive roller ofFIG. 2 having a rubber hardness of 35 degree (JIS A) of the presentinvention was obtained.

EXAMPLE 2

A semi-electrically conductive roller was prepared in the same manner asin EXAMPLE 1 except that a carbon fluoride (F/C=0.55) having afluorine-content of 47% by weight was used.

Comparative Example 1

A roller was prepared in the same manner as in EXAMPLE 1 except that acarbon black which was not fluorinated was used instead of the carbonfluoride.

Comparative Example 2

A roller was prepared in the same manner as in EXAMPLE 1 except that acarbon black which was completely fluorinated (i.e. F/C=1.1 (fluorinecontent 63%)) was used instead of the carbon fluoride.

Comparative Example 3

The carbon fluoride of EXAMPLE 1 and the carbon black of COMPARATIVEEXAMPLE 1 were mixed in a ratio of 4:1 (weight) to obtain a powderhaving an average F/C of 0.58 (fluorine content 48%).

The procedures of EXAMPLE 1 were repeated by using the powder to preparea semi-electrically conductive roller.

Comparative Example 4

The semi-electrically conductive roller prepared as above wasincorporated as a charging roller in the electrostatic copying machineshown in FIG. 1. The toner filming property with time lapsing and theelectrical properties, i.e. volume specific resistance and breakdownvoltage were evaluated. The results are shown in Table 1.

The evaluation and measurement are as follows:

(1) Resistance to toner filming (ranking): Adhesion condition of toneron the surface of charging roller was observed after operating themachine of FIG. 1 for 100 hours and 300 hours. Evaluation is conductedon the basis of the following ranks. RANK 1 . . . Toner on the rollersurface can be easily wiped with a cloth. RANK 2 . . . A slight tonerremains after the wiping. RANK 3 . . . Cannot be wiped completely toleave a thin toner layer. RANK 4 . . . Toner is sticked strongly to theroller surface.

(2) Volume specific resistance (electrically resistive monolayer): Athin aluminum plate (thickness 0.5 mm) is coated with an electricallyresistive material by dipping method so as to be a thickness of 50 μm toprepare a sample. After the sample is stayed for 16 hours in anatmosphere of 20° C. and 60% relative humidity, a volume specificresistance is measured by using a cell for measuring resistance(Resistivity Chamber R12702A: Kabushiki Kaisha Advantest) and anohm-meter (Digital Super High Ohm-meter R8340A: Kabushiki KaishaAdvantest). An electrical resistance of the roller is measured, afterstaying the sample for 16 hours in an atmosphere of 20° C. and 60%relative humidity, by using a copper tape of 10 mm width (Scotch TapeNo. 1245: SUMITOMO THREE M Co., Ltd.) as an electrode, and an ohm-meter(Digital Super High Ohm-meter R8340A: Kabushiki Kaisha Advantest) wherea distance between a main electrode and a guard electrode is 1 mm.

(3) Breakdown voltage: After staying a roller of sample for 16 hours inan atmosphere of 20° C. and 60% relative humidity, a direct voltagewhich is applied between a main electrode of 10 mm width and a coreroller is increased gradually, a lowest voltage at which breakdown iscaused is measured.

As is clear from Table 1, in comparison with the rollers of theCOMPARATIVE EXAMPLES the roller of the present invention is excellent inresistance to toner filming, and can be used as a good charging roller.

                                      TABLE 1                                     __________________________________________________________________________                 Ex. 1   Ex. 2   Com. Ex. 1                                                                            Com. Ex. 2                                                                           Com. Ex. 3                        __________________________________________________________________________    Resistive Materials                                                           Added materials                                                                            Carbon fluoride                                                                       Carbon fluoride                                                                       Non-fluorinated                                                                       Completely-                                                                          Mixture of Ex. 1                               (F/C = 0.95)                                                                          (F/C = 0.55)                                                                          carbon black                                                                          fluorinated                                                                          and Com. Ex. 1 at                                              (F/C = 0)                                                                             carbon black                                                                         4:1 (weight)                                                           (F/C = 1.1)                                                                          (Av. F/C = 0.58)                  Volume specific                                                                            2.8 × 10.sup.11                                                                 3.8 × 10.sup.8                                                                  2.6 × 10.sup.3                                                                  4.7 × 10.sup.13                                                                7.2 × 10.sup.5              resistance (Ω cm)                                                       Semi-electrically                                                             conductive roller                                                             Resistance to toner filming                                                   100 hours     1       1       3      --      3                                300 hours     1       2       4      --      4                                Volume specific                                                                            7 × 10.sup.11                                                                   2 × 10.sup.6                                                                    6 × 10.sup.5                                                                    >10.sup.14                                                                           5 × 10.sup.7                resistance (Ω cm)                                                       Breakdown voltage (kV)                                                                     >3      2.8     2.3     >3     2.4                               Total evaluation                                                                           Good    Good    Too low No good                                                                              Low performance,                                               resistance and                                                                        because                                                                              even though average                                            easily  electrically                                                                         fluorination is                                                breakdown.                                                                            insulative.                                                                          about the same as                                                             Ex. 2                             __________________________________________________________________________

The completely fluorinated coarbon black could not be used as asemi-electrically conductive roller, because it is electricallyinsulative (COMPARATIVE EXAMPLE 2). When using the non-fluorinatedcarbon black as a semi-electrically conductive roller (COMPARATIVEEXAMPLE 1), it is necessary to reduce an amount of carbon black becauseof its lower electrical resistance. In such a case, since an electricalresistance drastically changes with an amount of carbon black and also adispersibility of carbon black to a fluorine-containing polymer is bad,the obtained roller is easy to cause breakdown. Further, since a surfaceroughness of the coating becomes large and a surface hardness becomeslow, the roller is bad in abrasion resistance, which results in shortlife.

On the other hand, when mixing the non-fluorinated carbon black and thecarbon fluoride as in COMPARATIVE EXAMPLE 3, though the averagefluorination degree is near the degree of EXAMPLE 2, the electricalresistance is lower than that in EXAMPLE 2. Further properties such asresistance to toner filming and breakdown voltage are not improved. Thereason is assumed that since the electrical conductivity is obtainedmainly from the non-fluorinated carbon black, this case is similar tothe case where an amount of the non-fluorinated carbon black is reducedas in COMPARATIVE EXAMPLE 1.

INDUSTRIAL APPLICABILITY

According to the composition of the present invention, various resinsand rubbers can be endowed with electrical conductivity andnon-tackiness.

Also, according to the paint composition of the present invention, anelectrically conductive and non-takifying coating can be formed on asurface of various molded articles or various substrates.

The semi-electrically conductive roller of the present invention is thesemi-electrically conductive roller manufactured by forming theelectrically conductive elastic layer and the electrically resistivelayer on the electrically conductive supporting body in that order.Since the fluorine-containing polymer which contains the fluorinatedcarbon black is used as the resistive layer, the following effects areobtained. That is, the toner filming is difficult to happen, because thenon-tackiness to toner is excellent and the fluorinated carbon black iswell compatible with the fluorine-containing polymer. In addition,because the breakdown is difficult to happen, a beautiful image withoutblack lines can be obtained, and further the degradation of roller andthe failure of high voltage generator seldom happen. From these effects,sufficient performances can be exhibited for the semi-electricallyconductive roller such as a charging roller.

We claim:
 1. A composition consisting essentially of (A) carbon fluorideparticles having a ratio F/C of fluorine atom to carbon atom of morethan 0.5 and less than 1.0, and (B) at least one resin material selectedfrom the group consisting of a thermoplastic resin, a thermosettingresin and a rubber; wherein the weight ratio of (A) to (B) is from 1/99to 30/70, and said composition imparts electrical conductivity andnon-tackifying property.
 2. The composition of claim 1, wherein the F/Cis more than 0.5 and not more than 0.95.
 3. The composition of claim 1,wherein the F/C is more than 0.5 and not more than 0.9.
 4. Thecomposition of claim 1, wherein the component (A) is prepared byfluorinating a carbon black with fluorine gas.
 5. The composition ofclaim 1, wherein the component (A) is prepared by fluorinating a carbonblack with fluorine gas at 200° to 600° C.
 6. The composition of claim4, wherein the carbon black is an electrically conductive carbon black.7. The composition of claim 1, wherein the thermoplastic resin of thecomponent (B) is a fluorine-containing resin, a polyamide or apolyamideimide.
 8. The composition of claim 1, wherein the thermosettingresin of the component (B) is a silicone resin.
 9. The composition ofclaim 1, wherein the rubber of the component (B) is a silicone rubber ora fluorine-containing rubber.
 10. The composition of claim 1, whereinthe rubber of the component (B) is selected from the group consisting ofstyrene-butadiene rubber, polyurethane rubber, nitrile rubber,chloroprene rubber and EPDM.
 11. A paint composition comprising thecomposition of claim 1 and liquid carrier.
 12. An electricallyconductive and non-tackifying property roller, manufactured by formingan electrically conductive elastic layer having a volume specificresistance of not more than 10⁵ Ωcm and an electrically resistive layerhaving a volume specific resistance of 10⁶ to 10¹² Ωcm on anelectrically conductive supporting body at least in that order, saidelectrically resistive layer being prepared by the composition ofclaim
 1. 13. The roller of claim 12, wherein the electrically resistivelayer constitutes the outermost layer.
 14. The roller of claim 12,wherein the volume specific resistance of the electrically resistivelayer is 10⁸ to 10¹² Ωcm.
 15. The composition of claim 2, wherein thecomponent (A) is prepared by fluorinating a carbon black with fluorinegas.
 16. The composition of claim 3, wherein the component (A) isprepared by fluorinating a carbon flack with fluorine gas.
 17. Thecomposition of claim 2, wherein the component (A) is prepared byfluorinating a carbon black with fluorine gas at 200° to 600° C.
 18. Thecomposition of claim 3, wherein the component (A) is prepared byfluorinating a carbon black with fluorine gas at 200° to 600° C.
 19. Thecomposition of claim 5, wherein the carbon black is an electricallyconductive carbon black.
 20. The composition of claim 1, wherein thecarbon fluoride particles have a fluorine content greater than 44.2 wt %and less than 61.4 wt %, and a balance of carbon.